Clean and skin the eel, and then cut it into chunks. In a large bowl, mix together 1 cup flour, seasonings, oil, garlic, onion, and pepper. Add the eel to this mixture and then marinate in the refrigerator for 1 hour.
Dredge the marinated eel in flour. In a saute pan over medium heat, sear the eel until golden brown, about 7 minutes. Add the white wine and cook until reduced by half. Add the butter and cook until it melts and browns slightly. Divide the eel among 4 serving plates and top with the butter sauce